This invention relates generally to devices for filtering and separating liquids. More particularly, the present invention relates to fuel filters for removing foreign particles and separating water from fuel of the fuel supply system of an internal combustion engine.
The absence of high standards of quality control in diesel fuel supplies dictates that an effective fuel filter be incorporated into the fuel supply system for a diesel engine. It is not uncommon for diesel fuel to have significant quantities of abrasive particles and water. The abrasive particles present the potential for permanent damage to components of the fuel injection pump. The abrasive particles can also adversely effect the performance of the pump by destroying the ability of the fuel injection pump to precisely meter and deliver fuel at high pressures. The presence of water in the diesel fuel supply can cause rusting of engine components, and during freezing conditions, can result in interruption of the fuel injection system and/or seizure of moving components.
A number of conventional fuel filters perform the dual function of removing particulate material from the diesel fuel and separating water from the fuel. Commonly, the fuel filters employ a disposable filter cartridge which is replaced at pre-established intervals of filter usage. U.S. Pat. No. 6,471,070 assigned to the assignee of the present invention, discloses such a fuel filter. When the fuel filters are installed in a fuel line having relatively high fuel pressure, the substantially planar upper surface of the top cap of these conventional filter cartridges has a tendency to bulge upward. The displacement of the top cap upper surface can result in fuel leakage and/or cause binding of the retainer collar mounting the filter cartridge to the filter base.